Fault simulation to validate fault-tolerance in Ada

This paper discusses software fault injection as a validation technique for fault tolerance in Ada safety critical applications. General software fault simulation techniques are discussed followed by their implementation in Ada applications. Aspects of the Ada language that require specific attention during fault tolerant design are discussed. An Ada case study has been used to illustrate how fault injection and observation of the consequent error propagation through a given design solution can help to assess fault tolerance strategies. Attempts to use fault tolerance raise language-specific issues; an example is given for the Ada language.